Two vehicle transportation system

ABSTRACT

A first and a second aircraft are detachably coupled where the first aircraft is configured to perform a vertical landing using a first battery while the first aircraft is unoccupied and the unoccupied first aircraft includes the first battery. In response to detecting a second, removable battery being detachably coupled to the first aircraft, a power source for the first aircraft is switched from the first battery to the second, removable battery. After the switch, the first aircraft takes off vertically using the second, removable battery while occupied. The detachably coupled first aircraft and second aircraft are flown using the second aircraft (the power to keep the detachably coupled first aircraft and second aircraft airborne comes exclusively from the second aircraft and not the first aircraft).

CROSS REFERENCE TO OTHER APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 16/418,171 entitled TWO VEHICLE TRANSPORTATION SYSTEM filed May21, 2019, which claims priority to U.S. Provisional Patent ApplicationNo. 62/684,906 entitled TWO VEHICLE TRANSPORTATION SYSTEM filed Jun. 14,2018, both of which are incorporated herein by reference for allpurposes.

BACKGROUND OF THE INVENTION

In metropolitan areas like New York City and the San Francisco Bay Area,traffic congestion on the freeways is only getting worse. Mass transitin those regions is similarly packed. New transportation solutions whichpermit people to more quickly and easily get from place to place withina city would be desirable.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention are disclosed in the followingdetailed description and the accompanying drawings.

FIG. 1A is a diagram illustrating an embodiment of a personaltransportation system before an occupant has entered the aircraft and asecond battery has been coupled to the aircraft.

FIG. 1B is a diagram illustrating an embodiment of a personaltransportation system after an occupant has entered the aircraft and asecond battery has been coupled to the aircraft.

FIG. 2A is a diagram illustrating an embodiment of an occupied, standingpersonal transportation system.

FIG. 2B is a diagram illustrating an embodiment of an unoccupied,standing personal transportation system.

FIG. 3 is a diagram illustrating an embodiment of a map with locationsassociated with a flight service provider.

FIG. 4 is a flowchart illustrating an embodiment of a process to switchfrom an internal battery as a power source to a removable battery.

FIG. 5 is a flowchart illustrating an embodiment of a process to switchfrom a removable battery as a power source to an internal battery.

FIG. 6A is a diagram illustrating a top view of an embodiment of adocking station for an aircraft.

FIG. 6B is a diagram illustrating an embodiment of an aircraftperforming a vertical landing into a docking station.

FIG. 6C is a diagram illustrating an embodiment of an aircraft in adocking station with an old removable battery removed.

FIG. 6D is a diagram illustrating an embodiment of an aircraft in adocking station with a new removable battery inserted.

FIG. 6E is a diagram illustrating an embodiment of an aircraft in adocking station where all batteries are removable.

FIG. 7 is a diagram illustrating embodiments of a removable batterywhich is configured for easy transport.

FIG. 8 is a flowchart illustrating an embodiment of a process to decidewhether to charge an internal battery off of a removable battery.

FIG. 9 is a flowchart illustrating an embodiment of a process to refrainfrom charging an internal battery off of a removable battery duringvertical takeoff or landing.

FIG. 10 is a diagram illustrating an embodiment of a two-aircraftpersonal transportation system.

FIG. 11A is a diagram illustrating an embodiment of a tilt rotoraircraft coupling itself to an aircraft with a removable battery.

FIG. 11B is a diagram illustrating an embodiment of a tilt rotoraircraft towing an aircraft with a removable battery.

FIG. 11C is a diagram illustrating an embodiment of a tilt rotoraircraft decoupling itself from an aircraft with a removable battery.

FIG. 12A is a diagram illustrating an embodiment of a conventionaltakeoff and landing aircraft which is used to transport an aircraft witha removable battery.

FIG. 12B is a diagram illustrating an embodiment of a conventionaltakeoff and landing aircraft towing an aircraft with a removablebattery.

FIG. 12C is a diagram illustrating an embodiment of a conventionaltakeoff and landing aircraft beginning a release of an aircraft with aremovable battery.

FIG. 12D is a diagram illustrating an embodiment of an aircraft with aremovable battery after being released by a conventional takeoff andlanding aircraft.

FIG. 13 is a flowchart illustrating an embodiment of a process to extendthe range of a first aircraft with the help of a second aircraft.

FIG. 14 is a flowchart illustrating an embodiment of a process to extendthe range of a first aircraft with the help of a second aircraft.

FIG. 15 is a flowchart illustrating an embodiment of a process torespond to a travel request based on an amount of stored charge in aremovable battery.

FIG. 16 is a flowchart illustrating an embodiment of a process torespond to a travel request based on an amount of stored charge in aremovable battery and an amount of stored charge in an internal battery.

FIG. 17 is a flowchart illustrating an embodiment of a process to selecta vehicle from the pool of vehicles that is capable of providingsufficient charge for travel.

FIG. 18 is a diagram illustrating an embodiment of a process to includein-use vehicles when selecting a vehicle from a pool, where the internalbattery of an in-use vehicle would not be charged prior to pickup of anext ride requester.

FIG. 19 is a diagram illustrating an embodiment of a process to includein-use vehicles when selecting a vehicle from a pool, where the internalbattery of an in-use vehicle is charged prior to pickup of a next riderequester.

DETAILED DESCRIPTION

The invention can be implemented in numerous ways, including as aprocess; an apparatus; a system; a composition of matter; a computerprogram product embodied on a computer readable storage medium; and/or aprocessor, such as a processor configured to execute instructions storedon and/or provided by a memory coupled to the processor. In thisspecification, these implementations, or any other form that theinvention may take, may be referred to as techniques. In general, theorder of the steps of disclosed processes may be altered within thescope of the invention. Unless stated otherwise, a component such as aprocessor or a memory described as being configured to perform a taskmay be implemented as a general component that is temporarily configuredto perform the task at a given time or a specific component that ismanufactured to perform the task. As used herein, the term ‘processor’refers to one or more devices, circuits, and/or processing coresconfigured to process data, such as computer program instructions.

A detailed description of one or more embodiments of the invention isprovided below along with accompanying figures that illustrate theprinciples of the invention. The invention is described in connectionwith such embodiments, but the invention is not limited to anyembodiment. The scope of the invention is limited only by the claims andthe invention encompasses numerous alternatives, modifications andequivalents. Numerous specific details are set forth in the followingdescription in order to provide a thorough understanding of theinvention. These details are provided for the purpose of example and theinvention may be practiced according to the claims without some or allof these specific details. For the purpose of clarity, technicalmaterial that is known in the technical fields related to the inventionhas not been described in detail so that the invention is notunnecessarily obscured.

Various embodiments of a personal transportation system are describedherein. In some embodiments, the personal transportation system is anaircraft which performs a vertical landing of an aircraft using a firstbattery where the aircraft is unoccupied when the vertical landing isperformed. In some embodiments, the first battery is an internal battery(e.g., that is not easily removable and/or swappable). In some otherembodiments, the first battery is (also) a removable battery (e.g., thefirst, removable battery is swapped out and the second, removablebattery is swapped in). The second, removable battery being detachablycoupled to the aircraft is detected. In response to detecting thesecond, removable battery being detachably coupled to the aircraft, apower source for the aircraft is switched from the first battery to thesecond, removable battery and after switching the switch power source, avertical takeoff of the aircraft is performed using the second,removable battery, wherein the aircraft is occupied when the verticaltakeoff is performed. The following figures describe some examples of apersonal transportation system and how it may be used to transport anoccupant.

FIG. 1A is a diagram illustrating an embodiment of a personaltransportation system before an occupant has entered the aircraft and asecond battery has been coupled to the aircraft. In the example shown,the aircraft (100 a) is an unoccupied aircraft which has flown to thepickup location shown and performed a vertical landing. For example, aswill be described in more detail below, the occupant (110 a) may haverequested a ride from some flight service provider and the unoccupiedaircraft (100 a) is dispatched to pick up the occupant.

In this example, the unoccupied aircraft (100 a) is a relativelylightweight aircraft which includes an exemplary propeller or rotor (102a) which rotates about a vertical axis of rotation. In other words, theaircraft is a vertical takeoff and landing (VTOL) aircraft. Although notshown here, in some embodiments, the aircraft includes wings so that theaircraft can perform (at least partially) wing-borne flight (e.g., whichis more efficient). For simplicity and ease of explanation, somefeatures which are not directly related to the technique are notnecessarily described herein. For example, a single rotor oriented torotate about a vertical axis of rotation (as shown here) will typicallyhave an anti-torque rotor. For simplicity and ease of explanation, sucha rotor is not shown or described herein. In some embodiments, theaircraft (100 a) has rotors which rotate about a longitudinal axis(e.g., rotors in a fixed position which can be turned off/on whendesired, or rotors which can change position or direction because theyare tilt rotors or they are rotors that are attached to a tilt wing).Any appropriate aircraft which is capable of performing a verticaltakeoff and/or landing may be used.

An internal (e.g., built in and/or not easily removable and/orswappable) battery (104 a) in the aircraft is used to power the rotorand other devices which require power when flying to the pickup locationshown here (e.g., sensors in the aircraft, actuators for controlsurfaces on the aircraft, electronics in the aircraft, etc.). In someembodiments, a charger and/or depot from which the unoccupied aircraftflies to the pickup location is located only a short distance away.Since the internal battery (104 a/104 b) only needs to power theaircraft for a short hop, this simplifies and/or reduces the amount,complexity, and/or weight of onboard power equipment (e.g., to quicklycharge/discharge the internal battery) that otherwise could be a largeburden on the exemplary vehicle.

At the pickup location, an occupant (110 a) with a second battery (112a) is waiting. In this example, the second (e.g., removable and/orportable) battery (112 a) has a larger capacity than the first battery(104 a) which was used to fly the unoccupied aircraft to the pickuplocation shown. The occupant inserts or otherwise couples (e.g.,electronically and physically) the removable battery (112 a) to theunoccupied aircraft and then gets into the seat (106 a). In someembodiments, the insertion of the battery is detected and this stateinformation is passed to a (flight) controller (120 a) which respondsaccordingly (e.g., switches power sources so that the vehicle runs offof the inserted removable battery).

The following figure shows the system after the removable battery hasbeen coupled to the aircraft and after the occupant has entered theaircraft.

FIG. 1B is a diagram illustrating an embodiment of a personaltransportation system after an occupant has entered the aircraft and asecond battery has been coupled to the aircraft. In the state shown, thesecond battery (112 b), which the occupant (110 b) brought with them, isnow inserted into and/or otherwise coupled to the multicopter and theoccupant (110 b) is now seated in the seat (106 b). In some embodiments,the occupant is mostly or entirely a passenger (e.g., the occupiedaircraft (100 b) is mostly or completely autonomous). Alternatively, insome embodiments, the occupant pilots the aircraft to the destination.

Once the second battery (112 b) is coupled to the aircraft and theoccupant is ready to take off, the now occupied multicopter (100 b)performs a vertical takeoff using the rotor (102 b). However, unlike thelanding shown in FIG. 1A (e.g., where power was supplied by the firstbattery 104 a), the power for the takeoff is now supplied by the second,removable battery (112 b). In this example, all of the power required tofly the occupied aircraft (100 b) is provided by the removable battery(112 b) and no charge or power is drawn from the internal battery (104b) (e.g., assuming that the removable battery (112 b) has sufficientpower). In some embodiments, this switch of power sources is controlledand/or initiated by the controller (120 b).

In some embodiments, in addition to providing the power to fly theoccupied aircraft (100 b) from the pickup location to the drop offlocation, the first battery (in this example, an internal or built-inbattery) 104 b is charged from the removable battery (112 b) duringtransport of the occupant.

In this example, the seat is an open-air seat with no windshield orenclosure. In ultra-light applications, this may be desirable since awindshield or other enclosure would add weight to the aircraft (bothwhen unoccupied (100 a) as well as when occupied (100 b)).Alternatively, in some embodiments, there is some lightweightwindshield, guard, or other protective features around the seat (106a/106 b), for example, to protect the occupant from the wind and/orrain. For example, there may be vinyl, see-through sides surrounding thefour sides of the seat where the front side can be pushed aside orrolled up for ingress and egress.

In some embodiments, protective sides or panels are removable orotherwise detachable (e.g., when the weather is warmer and/or nicer).Having removable sides or panels would permit slightly heavier sides orpanels (e.g., which might offer better thermal insulation and/orprotection from the wind, rain, and/or snow) to be used during badweather and removed (e.g., which makes power consumption more efficient)when the weather is good. In some embodiments (not shown here), a seator cockpit includes safety device(s) to secure or otherwise restrain theoccupant. For example, seat 106 a/106 b may include shoulder and/or lapbelts, a five point harness, or other straps to secure the occupant.

In this example, the second, removable battery (112 b) is inserted intoa space or compartment below the seat (106 b) because this is aconvenient location (e.g., it permits a flat surface for the multicopterto land on, the space was already there due to the shape of the seat,and it does not require the occupant to lift the removable battery abovetheir head). In some other embodiments (e.g., described below), asecond, removable battery is inserted into or otherwise attached to theaircraft at some other location or position.

Generally speaking, the unoccupied aircraft (100 a) in FIG. 1A (i.e.,without the occupant (110 a) and without the removable battery (112 a))is designed to be a relatively small fraction of the mass or weightcompared to the occupied aircraft (100 b) in FIG. 1B (i.e., with theoccupant (110 b) and with the removable battery (112 b)). For example,the weight of the unoccupied aircraft (100 a) may be 50-70% or less ofthe weight of the occupied aircraft (100 b). This enables the built-inbattery (104 a) to have a relatively small capacity since it is onlyused when the aircraft is unoccupied. The removable battery (112 a/112b) has a larger capacity than the built-in battery (104 a/104 b) becauseit will need to fly the aircraft when it is occupied and thus muchheavier.

The aircraft shown in FIG. 1A and FIG. 1B is merely exemplary and otherembodiments may have other features and/or be configured differently.The following figures show an example of an aircraft where the occupantstands.

FIG. 2A is a diagram illustrating an embodiment of an occupied, standingpersonal transportation system. In the example shown, occupied aircraft200 a has performed a vertical landing. In this example, the aircraft isa multicopter with multiple rotors (202) which rotate about a verticalaxis which permits the aircraft to perform vertical takeoffs andlandings. To preserve the readability of this figure, a controller isnot shown in this example but various management and/or controloperations (e.g., switching power sources in response to removal of theremovable battery) is done by a controller.

Unlike the previous example, in this example, both the internal battery(204 a) and the removable battery (212 a) are both located above theoccupant's head, near the rotors and other devices which require power.For example, with the removable battery (212 a) located closer to thepower loads, less electrical wiring needs to be routed. In contrast, inFIG. 1B, there would be electrical wiring from the top of the aircraft(e.g., near internal battery 104 b) to the bottom of the seat (106 b) sothat the removable battery (112 b) which is beneath the seat can beelectrically connected to the other electrical devices.

In this example, the internal battery (204 a) and the removable battery(212 a) are stacked vertically with the removable battery located belowthe internal battery and above the compartment (220 a). In someapplications this is desirable because then the occupant does not haveto lift the battery as high and/or a shorter occupant will have aneasier time getting the removable battery in and out. For example, ifthe two batteries were arranged vertically but the removable battery wason top, then the occupant would have to lift the battery higher and ashorter occupant would find this more difficult.

Another difference compared to the previous example is how the aircraftcarries the occupant. In this example, the occupant (210 a) standsduring the ride in a compartment (220 a). The exemplary compartment hasan accordion-style door (222 a) for the occupant to get in and out. Inother words, the compartment resembles a telephone booth. This type ofcompartment may be attractive because it more easily permits theoccupant to bring luggage on board the aircraft and it permits occupantsin wheelchairs to use the aircraft.

In some embodiments, the compartment may include safety features toprevent the occupant from falling. For example, the compartment mayinclude straps or bars for the occupant to hold on to during the ride.In some embodiments, the compartment includes a folding and/or jump seat(e.g., with or without seatbelts, a harness, etc.).

The aircraft embodiments described above include a seat (e.g., for theoccupant to sit in, FIGS. 1A and 1B) and a compartment (e.g., for theoccupant to stand it, FIGS. 2A and 2B). Any appropriate device orcompartment may be used to hold or otherwise transport the occupant,including a cockpit, a bicycle-style seat, a backless seat, a saddle,etc. In some embodiments, cargo is transported (e.g., in addition toand/or as an alternative to a passenger or occupant).

FIG. 2B is a diagram illustrating an embodiment of an unoccupied,standing personal transportation system. In the state shown, theoccupant (210 b) has exited the aircraft (200 b) and has taken theremovable battery (212 b) out. The unoccupied aircraft (200 b) thentakes off vertically using the internal battery (204 b).

In some embodiments, the exemplary aircraft described above are part ofa transportation service which provides flights to people who requestthem. The following figure shows an example of this.

FIG. 3 is a diagram illustrating an embodiment of a map with locationsassociated with a flight service provider. In this example, an occupant(not shown) has requested a flight to work. An unoccupied aircraft (see,e.g., unoccupied aircraft 100 a in FIG. 1A and unoccupied aircraft 200 bin FIG. 2B) is sent from a source depot (300) to the occupant's house(i.e., the pickup location) (302). In this example, depots are locationswhere unoccupied aircraft (such as the one shown in FIG. 1A) can chargeand/or wait for their next assignment. An unmanned aircraft is selectedfrom depot 300 (as opposed to other depots) because that is the depotlocated closest to the pickup location (302). At the pickup location(302), the unoccupied aircraft lands vertically. Landing vertically isattractive or otherwise desirable, because the aircraft has a smallerlanding footprint compared to an aircraft which performs a traditional(e.g., wing-borne) landing and can land in more densely-packed areas(e.g., San Francisco, as shown in this example). As described above,during this first leg, the unoccupied aircraft has power using theinternal battery.

At the pickup location (302), the occupant, with their removable batteryinserted into and/or otherwise attached to the aircraft, is then flownfrom the pickup location (302) to the drop off location (304), which inthis example is the occupant's office. As described above, this secondleg is powered using the removable battery (see, e.g., FIG. 1B) and insome embodiments, the internal battery is charged off of the removablebattery.

It is noted the aircraft embodiments described herein are independentand/or agnostic with respect to the flying technology and/or techniqueused to fly the occupied aircraft. To put it another way, in someembodiments, autonomous flying techniques and/or processes are used tofly the occupied aircraft from the pickup location (302) to the drop offlocation (304) (i.e., the occupant is strictly an occupant and does nothave to fly or otherwise instruct the aircraft). Alternatively, theoccupant may also be a pilot who flies or otherwise instructs theaircraft (e.g., even if the aircraft is at least semi-autonomous).

At the drop off location (304), the occupant gets off and takes theirremovable battery with them. See, for example, FIG. 2A and FIG. 2B. Atwork, the occupant charges the removable battery (not shown), which hasbeen at least partially depleted of charge or power during the flightfrom home (302) to work (304). Meanwhile, the aircraft (which isunoccupied once again) flies from the drop off location (304) to adestination depot (306) where the internal battery is charged and/or theaircraft awaits its next assignment. During this third leg, the internalbattery is used to power the unoccupied aircraft. See, for example FIG.2B.

At the end of the day (e.g., when the removable battery has had manyhours to charge), the occupant requests a flight home and the sequenceis reversed (not shown). Once home for the night, the occupant willcharge their removable battery overnight at their home so that it isfully charged for the next morning's flight (if needed).

Alternatively, in some embodiments, the removable battery stays at ornear the drop off location (e.g., 304) and the removable battery ischarged there. For example, there may be designated pickup and drop offlocations and the occupant or attendant may leave the battery in somecharging locker or array of chargers at the designated pickup and dropoff location where it will remain until collected. In some embodiments,each battery has an owner or assigned or designated user (e.g., so thatthe same user tends to use to the same battery). Alternatively, thebatteries may not be designated for or assigned to a particular user andare selected or otherwise used on a first come, first serve basis.

One benefit to this type of aircraft is that it can be used to quicklytransport people, even in dense cities with traffic congestion. Forexample, driving from the western side of San Francisco to the easternside of San Francisco can take anywhere from 30 minutes to an hour,depending upon traffic. The ability to take off and land verticallypermits this type of aircraft to be used even in dense cities withlittle free space (e.g., there is no need for a long runway which aconventional takeoff and landing aircraft would require). Once airborne,flying avoids all of the traffic congestion on the ground, and permitsthe occupant to get from one location to another quickly and easily.

In some embodiments, a depot (e.g., 300 or 306) or designated landingsite (e.g., 302 or 304) is/are located on the roof of a building. Forexample, using the roof of a building may be attractive for a number ofreasons. From a noise perspective, it may be less noisy if an aircraftstays higher up and does not come down to the ground level. Also, usingrooftops may be safer during takeoff and landing because the area may bemore controllable and/or better secured with fewer passersby. In denselycrowded areas, there may also be fewer locations on the ground withenough clear space necessary for takeoff and landing; rooftops may offersome of the last securable and flat space available in such areas.

In some embodiments, a removable battery stays at a landing site (e.g.,where the occupant gets out of the personal transportation system) andthe removable battery is charged at the landing site (e.g., instead ofat the occupant's house or place of work). In some embodiments where thelanding site is located on the roof of a building, solar panels or otherrenewable sources of energy are used to charge the removable batteriesbeing charged there.

The following flowcharts describe the examples of FIGS. 1A-2B moregenerally and/or formally.

FIG. 4 is a flowchart illustrating an embodiment of a process to switchfrom an internal battery as a power source to a removable battery. Insome embodiments, the process is performed by a controller (e.g., aflight controller) in personal transportation system 100 a and 100 b inFIG. 1A and FIG. 1B (e.g., when an occupant boards a personaltransportation system and inserts or otherwise couples their removablebattery to the personal transportation system).

At 400, a vertical landing of an aircraft is performed using a firstbattery, wherein the aircraft is unoccupied when the vertical landing isperformed, the unoccupied aircraft includes the first battery, and theunoccupied aircraft excludes a second, removable battery. See, forexample, the vertical landing performed by unoccupied aircraft 100 a inFIG. 1A. The removable battery (112 a) is not connected or otherwisecoupled to the unoccupied aircraft (100 a) so the internal battery (104a) supplies the power for the vertical landing.

At 402, the second, removable battery being detachably coupled to theaircraft is detected. That is, the removable battery is coupled to theaircraft in a manner where the two can subsequently be decoupled ordetached from each other, and (e.g., temporary) coupling or a connectionbetween the removable battery and aircraft is detected (e.g.,mechanically and/or electrically). For example, going from FIG. 1A toFIG. 1B, removable battery 112 b is now coupled (e.g., removably and/ortemporarily) to aircraft 100 b in FIG. 1B. Any appropriate (e.g.,physical and/or electrical) technique and/or components to detect thecoupling of the removable battery to or with the aircraft may be used.

At 404, in response to detecting the second, removable battery beingdetachably coupled to the aircraft, a power source for the aircraft isswitched from the first battery to the second, removable battery. Forexample, although not shown in FIG. 1A and FIG. 1B (e.g., to preservereadability), aircraft 100 a/100 b may include electrical componentswhich select the power source(s) for rotor 102 a/102 b and othercomponents which require power. In FIG. 1A, since internal battery 104 ais the only power source available, that battery is selected as thepower source. In FIG. 1B, to conserve the power in internal battery 104b and since removable battery 112 b is now available to the aircraft,removable battery 112 b is selected as the power source.

At 406, after switching the switch power source, a vertical takeoff ofthe aircraft is performed using the second, removable battery, whereinthe aircraft is occupied when the vertical takeoff is performed. See,for example, FIG. 1B, where removable battery 112 b is used to power thevertical takeoff and internal batter 104 b is not used to power thevertical takeoff.

FIG. 5 is a flowchart illustrating an embodiment of a process to switchfrom a removable battery as a power source to an internal battery. Insome embodiments, the process is performed by a controller (e.g., aflight controller) in personal transportation system 200 a and 200 b inFIG. 2A and FIG. 2B (e.g., when an occupant disembarks from a personaltransportation system and removes or otherwise decouples their removablebattery from the personal transportation system).

At 500, a vertical landing of an aircraft is performed using a second,removable battery, wherein the aircraft is occupied when the verticallanding is performed and the second, removable battery is detachablycoupled to the occupied aircraft. For example, to conserve the power ofinternal battery 204 a, only removable battery 212 a is used to performthe vertical landing in FIG. 2A.

At 502, the second, removable battery being decoupled from the aircraftis detected. See, for example, the transition from FIG. 2A to FIG. 2B.The occupant exits the aircraft and takes out or otherwise decouplesremovable battery 212 b from aircraft 200 b. As described above, anyappropriate (e.g., physical and/or electrical) technique and/orcomponents to detect the removal or decoupling of the removable batteryfrom the aircraft may be used.

At 504, in response to detecting the second, removable battery beingdecoupled from the aircraft, a power source for the aircraft is switchedfrom the second, removable battery to a first battery. See, for example,FIG. 2B. Since removable battery 212 b is no longer available as a powersource to unoccupied aircraft 200 b, internal battery 204 b is selectedas the power source.

At 506, after switching the switch power source, a vertical takeoff ofthe aircraft is performed using the first battery, wherein the aircraftis unoccupied when the vertical takeoff is performed, the unoccupiedaircraft includes the first battery, and the unoccupied aircraftexcludes the second, removable battery. See, for example, the verticaltakeoff shown in FIG. 2B.

In some embodiments, a device is used to help insert or remove aswappable battery from an aircraft. The following figure shows oneexample.

FIG. 6A is a diagram illustrating a top view of an embodiment of adocking station for an aircraft. In the example shown, the dockingstation (600 a) has an isosceles triangle base (602) with inwardlysloping sides (604). An aircraft with a matching base is designed toperform a vertical landing and land in the docking station. The shape(in this example, an isosceles triangle but any appropriate shape may beused) enforces a single proper landing position for the aircraft (e.g.,the shape of the docking station ensures that the aircraft always landswith the accordion-style door parallel to the shortest wall of thedocking station). Enforcing a single proper landing position helps toensure that any removable battery coupled to the aircraft can be safelydetached from the aircraft and/or any new removable battery can besafely coupled to the aircraft.

The following figure shows a side view of an occupied aircraft landingin the exemplary docking station.

FIG. 6B is a diagram illustrating an embodiment of an aircraftperforming a vertical landing into a docking station. In the exampleshown, the aircraft (610 b) is performing a vertical landing into thedocking station (600 b). The aircraft (610 b) is configured in thisexample to have a removable battery (612 b) attached or otherwisecoupled to the bottom of the aircraft. This permits the docking stationto have access to the removable battery for removal (e.g., of an oldone) and/or insertion (e.g., of a new one). In this example, the dockingstation (600 b) is used to remove or otherwise decouple an old battery(612 b) from the aircraft and insert or otherwise coupled a new battery(614 b) to the aircraft.

As shown from this view, the sloped sides of the docking station helpthe aircraft to properly land in the docking station, even if thealignment is slightly off. In this example, the aircraft (610 b) isslightly to the left of the docking station (600 b). However, theinwardly sloping sides of the docking station will center the aircraftso that it lands properly and/or correctly within the docking station.

FIG. 6C is a diagram illustrating an embodiment of an aircraft in adocking station with an old removable battery removed. In the exampleshown, the aircraft (610 c) has landed in the docking station (600 c)and has turned its rotors off so that it no longer needs power from the(old) removable battery (612 c). Once it is safe to do so, the (old)removable battery (612 c) in the aircraft is removed using the dockingstation (600 c).

FIG. 6D is a diagram illustrating an embodiment of an aircraft in adocking station with a new removable battery inserted. In the exampleshown, the aircraft (610 d) is still in the docking station (600 d). Thedocking station (600 d) has inserted the (new) removable battery (614 d)into the aircraft (610 d). Naturally, in some cases, only a removal ordecoupling is performed, or only an insertion or coupling is performed.For completeness, both a decoupling and a coupling are shown in thisexample.

One benefit to using a docking station (one embodiment of which is shownhere) to handle the removable battery is that the docking station may beable to more safely and/or gently decouple (e.g., remove) and/or couple(e.g., insert) removable batteries from/to the aircraft. For example,some people may misalign the batteries or push/pull too hard wheninserting or removing the batteries, all of which could damage thebattery and/or the aircraft. The risk of electric shock is alsodecreased if the docking station handles the battery. Another benefit isthat a docking station may be faster at swapping out removable batteriescompared to a human. For example, during peak times, a fast turnaroundtime may be desirable if there is a line for aircraft at a predeterminedpickup/drop off location. The docking station also frees up an occupantso that they can focus on carrying in/out any luggage, helping youngchildren, etc.

FIG. 6E is a diagram illustrating an embodiment of an aircraft in adocking station where all batteries are removable. In this example, theaircraft lands in docking station 620 using a first battery (622) whichis removable (for brevity, the landing is not shown). Once in thedocking station, the first battery (622) is swapped out, as is shownhere. Then, a second battery (624), which is removable and fullycharged, is swapped into the aircraft (not shown). The aircraft can thentake off (not shown) using the second battery (624).

Such embodiments (e.g., where all of the batteries are removable) may bedesirable because then expensive and/or heavy power components to chargeand/or discharge an internal battery quickly do not need to be includedin the aircraft. In contrast, if an internal battery had to fly theunoccupied aircraft to or from a depot or other location, then expensiveand/or heavy power components would need to be included in the aircraftwhich adds to the expense and weight. As shown here, in someembodiments, the first battery which is used during a vertical landing

In some applications, the occupant of an aircraft will transport theremovable battery with them to their final destination and charge itthere. As such, in some embodiments, a removable battery includesfeatures to make transport and/or charging more convenient. Thefollowing figure shows some exemplary features which make transport ofthe removable battery easier.

FIG. 7 is a diagram illustrating embodiments of a removable batterywhich is configured for easy transport. In the example shown, battery700 has shoulder straps (702) which permit the removable battery to becarried like a backpack. Alternatively, a battery may have a singlestrap (not shown) so that the battery is carried across the body (e.g.,like a messenger bag), over the shoulder (e.g., like a shoulder bag), orcarried by hand (e.g., like a briefcase).

In some cases, a pickup location and/or drop off location may not beclose to the occupant's actual location prior to pick up and/or desired(e.g., final) destination. For example, there may be designated and/orpermitted locations at which a pickup or a drop off is permitted tooccur (e.g., due to zoning restrictions). By including straps or otherfeatures which make the removable battery easier to transport, it iseasier for the occupant to transport the removable battery from a dropoff location to their final destination, or from their home or office toa pickup location.

In this example, a charging port (704 a) is located at the top of theremovable battery (700). Diagram 704 b shows a close-up view of thecharging port (704 a) when a cap (706 b) is closed. The cap covers anopening or cavity (708 b) in which is stored a three-prong maleelectrical plug (710 b) with a retractable cord (712 b). Diagram 704 cshows the same view as diagram 704 b, but with the cap (706 c) no longercovering the opening (708 c) and the plug (710 c) and retractable cord(712 c) extended. Including all of the necessary cords and cable tocharge the removable battery (700) is desirable because then the persondoes not need to bring or pack those cords. It is also noted thethree-prong male electrical plug (710 b/710 c) works with standardelectrical outlets, which (as described above) is a benefit because noexpensive and/or fast charging technology and/or equipment is required.

Removable battery 720 shows another embodiment where the removablebattery includes a telescoping handle (722) and a plurality of wheels(724) so that the removable battery can be wheeled about like a rollingsuitcase. The top of the removable battery also includes a charging port(726). In some embodiments the charging port is implemented as shown indiagram 704 b and 704 c. Alternatively, the charging port may beimplemented in some other manner.

As described above, in some embodiments, an internal battery (ifincluded in an aircraft) is charged from the removable battery while theremovable battery is electrically coupled to the aircraft. The followingfigures describe some example decision making processes associated withcharging an internal battery off of a removable battery.

FIG. 8 is a flowchart illustrating an embodiment of a process to decidewhether to charge an internal battery off of a removable battery. Forexample, in FIG. 3, this example process could be used to decide whetherto charge an internal battery off of a removable battery during thesecond or occupied leg of the trip shown in FIG. 3 (e.g., between pickuplocation 302 and drop off location 304). In some embodiments, aremovable battery has a larger capacity than the internal battery whichpermits the former to charge the latter. In some embodiments, theprocess is performed soon after a removable battery is inserted orotherwise coupled to an aircraft (see, e.g., FIG. 1B).

At 800, a pickup location and a drop off location are received. Forexample, in FIG. 3, the occupant of the aircraft may have specified adesired pickup location (302) and drop off location (304) whenrequesting a flight and/or prior to an aircraft being sent to performthe pickup.

At 802, an amount of travel-related charge is estimated based at leastin part on the pickup location and the drop off location. For example,in FIG. 3, the amount of charge associated with flying from pickuplocation (302) and drop off location (304) would be estimated.

At 804, an amount of stored charge in the removable battery is measured.For example, in FIG. 1B, when the removable battery (112 b) is insertedinto or otherwise coupled with aircraft 100 b, a measure of the amountof charge or power in removable battery (112 b) is performed.

At 806, it is decided whether to charge an internal battery from theremovable battery based at least in part on the amount of travel-relatedcharge and the measured amount of stored charge in the removablebattery. Generally speaking, if the measured amount of stored charge inthe removable battery (e.g., obtained at 804) minus the amount of chargeto fly from the pickup location to the drop off location (e.g.,estimated at 802) is relatively high, then the removable battery hassufficient reserves or leftover charge (e.g., after supplying the powerto travel between the pickup location to the drop off location) tocharge the internal battery. In one example, if this difference (orreserve) is greater than some threshold, it is decided to charge theinternal battery from the removable battery. To put it another way, theremovable battery will still have a lot of leftover charge even afterflying from the pickup location to the drop off location, so why not usethis extra charge to charge the internal battery?

In some embodiments, the decision at step 806 takes into account thestate of the flight or transportation system as a whole. For example,during the morning or evening rush hour, there may be more demand forflights and it would be undesirable for an aircraft to sit in a depot sothat its internal battery can be charged during such periods of highdemand. In some embodiments, during periods of high demand (e.g., duringpredefined times corresponding to historically high demand or based onreal-time demand measurements), internal batteries are more aggressivelycharged using the removable batteries. In some embodiments, as demandfor rides or aircraft goes up (e.g., based on historic information orreal-time measurements), a threshold (e.g., against which the differencebetween the measured charge and the amount of travel-related charge iscompared) goes down. In other words, the internal batteries will becharged off of removable batteries with less reserve as demand forflights goes up.

In some embodiments, the amount of charge in the internal battery istaken into account at step 806. For example, the amount of charge in theinternal battery could also be measured. If the internal battery isalmost fully charged, then it may not be necessary to charge theinternal battery. In some embodiments, an internal battery is charged ifa measured amount of charge in the internal battery is less than a firstthreshold and the reserve in the removable battery (e.g., the differencebetween a measured amount of charge in the removable battery and howmuch will be consumed by the flight from the pickup location to the dropoff location) is greater than a second threshold.

If it is decided to charge the internal battery from the removablebattery at 806, then at 808 the internal battery is charged from theremovable battery. Otherwise, the internal battery is not charged fromthe removable battery at 810.

Even if it is decided to charge the internal battery from the removablebattery, there may be times during the flight when it is undesirable todo so. The following figure describes an example of this.

FIG. 9 is a flowchart illustrating an embodiment of a process to refrainfrom charging an internal battery off of a removable battery duringvertical takeoff or landing. In some embodiments, this process isperformed while an internal battery is being charged from a removablebattery (e.g., at step 808 in FIG. 8). As described above, the personaltransportation systems described herein perform vertical takeoff andlanding. The most power-intensive part of the flight for such aircraftis during the vertical takeoff and landing. As such, in this example, nocharging of the internal battery is performed during this time.

At 900, there is a temporary pause in charging the internal battery fromthe removable battery during a vertical takeoff. For example, asoccupied aircraft (100 b) in FIG. 1B ascends vertically, internalbattery 104 b would not be charged off of removable battery 112 b. Thispermits all of the charge or power in removable battery 112 b to be usedtowards the vertical takeoff which is power intensive.

During the flight (e.g., between the vertical takeoff at step 900 andthe vertical landing at 902), the internal battery is charged using theremovable battery. This part of the flight may be less power intensiveand so it may be acceptable to charge the internal battery from theremovable battery. This is especially true if the aircraft embodimentincludes wings for at least partial wing borne flight.

At 902, there is a temporary pause in charging the internal battery fromthe removable battery during a vertical landing. For example, asoccupied multicopter 200 a in FIG. 2A performs a vertical landing,internal battery 204 a would not be charged off of removable battery 212a.

In some embodiments, an occupied personal transportation system may stopforward flight and hover in air. For example, the pilot or autonomousflight process may detect an obstruction in the flight path and stopforward movement, causing the aircraft to hover in the air. Mid-airhovering, like vertical takeoff and landing, is very power intensive andin some embodiments charging of the internal battery from the removablebattery is temporarily paused if this occurs.

Returning briefly to FIG. 3, the practical size and weight limitationsof the removable battery mean that the range of the personaltransportation system is limited. The following figures describe someembodiments for how the range of a personal transportation system may beincreased.

FIG. 10 is a diagram illustrating an embodiment of a two-aircraftpersonal transportation system. In the example shown, a personaltransportation system with a removable battery (see, e.g., FIGS. 1A-2B)has a range represented by circle 1000 given pickup location 1002. Forexample, the radius of range 1000 may vary depending upon the capacityof a removable battery (and, if desired, the capacity of a personaltransportation system's internal battery as well). In this example, therange (1000) corresponds roughly to the size of a city, in this exampleSan Francisco.

To support a larger (e.g., metropolitan area) transportation system, atwo-aircraft configuration may be used as is shown in this example.During a first segment or leg (1004), an occupied aircraft or personaltransportation system (for convenience, sometimes referred to as a firstaircraft) flies to some location using the power from the removablebattery as described above. In this example, this first leg (1004) isrelatively short and takes place entirely within the city limits of SanFrancisco.

Then, with the first aircraft in the air, a second aircraft detachablyor removably couples itself to the personal transportation system andtows or otherwise transports the first aircraft over a second leg(1006). As shown here, this second leg (1006) extends from San Franciscoto San Jose and is a much longer distance compared to the first leg(1004). During this leg, the second aircraft supplies all of the liftnecessary to keep both the first aircraft and the second aircraftairborne. This permits the first aircraft to consume little or no power(e.g., from the removable battery over this relatively long second leg(1006)).

Once the two aircraft get close to the drop off location (1008), the twoaircraft decouple from each other. The first aircraft then completes therelatively short third leg (1010) from the decoupling location to thedrop off location (1008), once again using power from its removablebattery as described above.

By using two aircraft to make the journey, an occupant can get from thepickup location (1002) to the drop off location (1008), even though thedrop off location is well outside of range 1000.

In various embodiments, any type of aircraft can be used (e.g., as thefirst aircraft or the second aircraft) and any appropriate connector orcoupler may be used to detachably or temporarily couple the two aircraftto each other. The following figures describe one example where a tiltrotor aircraft is used as the second aircraft.

FIG. 11A is a diagram illustrating an embodiment of a tilt rotoraircraft coupling itself to an aircraft with a removable battery. In theexample shown, the first aircraft (1100 a) is an occupied aircraft witha removable battery (1122 a). The first aircraft (1100 a) performs avertical takeoff using the power from a removable battery as describedabove. In this example, the aircraft includes a loop (1102 a) whichextends upward above the aircraft's rotor. For convenience, the aircraftfrom FIG. 1B is shown as the first aircraft (1100 a) but naturally anyappropriate personal transportation system and/or aircraft may be used.

Once the first aircraft (1100 a) has ascended to some location where thecoupling will occur, the first aircraft stops its ascent and hoversmidair. For simplicity, in this example the first aircraft (1100 a) isshown to ascend strictly vertically (e.g., without any forward and/orlateral movement) and the second aircraft (1104 a) comes to the firstaircraft. In some embodiments, the first aircraft flies (e.g., movesforward and/or laterally) to some rendezvous point where the couplingwill occur (e.g., over water, over a large open space, in some permittedairspace, etc.).

With the first aircraft (1100 a) hovering midair, the second aircraft(1104 a) couples itself to the first aircraft using a hook (1106 a) onthe underside of the second aircraft. The hook (1106 a) is designed tograb and hold the loop (1102 a) on the first aircraft so that the firstaircraft can be towed by the second aircraft.

It is noted that the second aircraft (1104 a) is a tilt rotor aircraftwhere the rotors can either be pointed downward (e.g., for hovering,vertical takeoff, vertical landing, etc.) or backward (e.g., for atleast partial wing-borne flight where the lift to stay airborne comes atleast partially from the wing). In the state shown in FIG. 11A, therotors (1108 a) of the second aircraft (1104 a) are pointing downward(e.g., in a hovering position) which permits the second aircraft tohover in the air and make small adjustments or movements along thevertical, yaw, and/or roll axes as desired. This ability to hover andmake small adjustments or movements may be desirable while the twoaircraft attempt to connect or otherwise couple to each other.

Once the two aircraft are coupled to each other using the hook (1106 a)and the loop (1102 a), the second aircraft switches its rotors from adownward (e.g., hovering) position to a backward (e.g., forward flight)position. The following figure shows the second aircraft with its rotorsin this position.

FIG. 11B is a diagram illustrating an embodiment of a tilt rotoraircraft towing an aircraft with a removable battery. In this example,the rotors (1108 b) of the second aircraft (1104 b) are now pointingbackward. With the rotors in this configuration, the second aircraft(1104 b) is able to cover large distances more efficiently (e.g.,compared to when the rotors are in the downward position) because of thelift from the wings. Returning briefly to FIG. 10, with the tilt rotorspointing backward as shown in FIG. 11B, the second aircraft (with thefirst aircraft in tow) can efficiently travel the second leg (1006) fromSan Francisco to San Jose. Returning to FIG. 11B, while the secondaircraft (1104 b) tows the first aircraft (1100 b), the rotor (1120 b)of the first aircraft (1100 b) is turned off, which permits the power inthe removable battery (1122 b) to be conserved.

It is noted that between FIG. 10A and FIG. 10B, the tilt rotors (1108a/1108 b) of the second aircraft (1104 a/1104 b) change position fromdownward to backward and the rotor (1120 a/1120 b) of the first aircraft(1100 a/1100 b) stops rotating. Any appropriate sequencing associatedwith these two changes may be used (e.g., the tilt rotors (1108 a/1108b) may change position first and then the single rotor (1120 a/1120 b)may stop, or vice versa).

The following figure shows the exemplary decoupling of the two exemplaryaircraft.

FIG. 11C is a diagram illustrating an embodiment of a tilt rotoraircraft decoupling itself from an aircraft with a removable battery. Inthis example, the first aircraft (1100 c) and the second aircraft (1104c) have decoupled from each other. For example, in any appropriate orderor sequence, the tilt rotors (1108 c) of the second aircraft (1104 c)return to a downward facing position (e.g., so that the second aircraftcan hover midair and more easily detach the hook (1106 c) from the loop(1102 c) using small movements and/or adjustments) and the rotor (1120c) of the first aircraft (1100 c) turns on. Once the two aircraft aredecoupled from each other, the first aircraft (1100 c) performs avertical landing using the power from the removable battery (1122 c) asdescribed above.

As described above, a variety of aircraft configurations and/orconnectors may be used. The following figure shows an example where thesecond aircraft is a fixed wing aircraft which performs a conventionaltakeoff and landing and is used to tow a first aircraft.

FIG. 12A is a diagram illustrating an embodiment of a conventionaltakeoff and landing aircraft which is used to transport an aircraft witha removable battery. In this example, the first aircraft (1200 a)performs a vertical takeoff. Once the first aircraft reaches a locationat which the coupling will occur, the first aircraft will hover in air.

A second aircraft (1202 a), which in this example performs wing-borneflight and conventional takeoff and landing, uses a claw or grabber(1204 a) which includes a plurality of pincers or fingers which can openand close to couple to the first aircraft. In the state shown here, thepincers of the claw (1204 a) are open. The second aircraft (1202 a)cannot hover midair and so must fly at or above some stall speed whencoupling to the hovering first aircraft. In some embodiments, anaircraft with a relatively low stall speed is selected so that thesecond aircraft can fly at relatively low(er) speeds to make thecoupling easier.

The first aircraft (1200 a) in this example has a loop (1206 a) whichpoints or faces upward. To couple the two aircraft together, the claw(1204 a) grabs on to the loop (1206 a) and closes its claws. A loop maybe attractive because it increases the target area for the claw to hitand generally makes it easier for the two aircraft to connect. Forexample, if the claw lands in the middle of the loop, the pull on theline will cause the claw to lift up and come into contact with the topof the loop, at which time the claw can close.

FIG. 12B is a diagram illustrating an embodiment of a conventionaltakeoff and landing aircraft towing an aircraft with a removablebattery. In the state shown, the claw (1204 b) has closed around theloop (1206 b) so that the second aircraft (1202 b) is towing the firstaircraft (1200 b). To conserve the power of the removable battery (1210b), the rotor (1212 b) of the first aircraft (1200 b) is turned off sothat all of the lift to keep two aircraft airborne (and the powerconsumed to that end) comes from the second aircraft (1202 b).

FIG. 12C is a diagram illustrating an embodiment of a conventionaltakeoff and landing aircraft beginning a release of an aircraft with aremovable battery. As described above, because the second aircraft (1202c) cannot hover midair and must fly at or above a stall speed, thesecond aircraft in this example decouples from the first aircraft (1200c) without stopping or otherwise hovering midair. To do this, the secondaircraft (1202 c) flies in a manner which causes the first aircraft(1200 c) to swing like a pendulum. In the state shown here, the firstaircraft (1200 c) is on the upswing, flying forwards. In this example,to initiate the swinging of the first aircraft, the second aircraftdescends, as shown here. Any appropriate maneuvering by the secondaircraft (1202 c) to cause the first aircraft (1200 c) to swing (e.g.,like a pendulum) may be used.

In this example, when the first aircraft (1200 c) is at or near the apexof its swing, the second aircraft (1202 c) will set the first aircraftdown on the ground. In some embodiments, for safety and/or to help witha softer landing, the rotor (1212 c) of the first aircraft (1200 c) isturned on prior to the decoupling and landing.

FIG. 12D is a diagram illustrating an embodiment of an aircraft with aremovable battery after being released by a conventional takeoff andlanding aircraft. In the state shown here, the first aircraft (1200 d)has been deposited on the ground by the second aircraft (1202 d) and theclaw (1204 d) has been opened so that the two aircraft can decouple. Thesecond aircraft (1202 d), having descended to deposit the first aircrafton the ground, begins to ascend again. In the state shown here, thefirst aircraft (1200 d) is in its downswing (e.g., it reached its apexand just began its downswing) when the first aircraft was deposited onthe ground. As described above, the first aircraft may be deposited onthe ground at any appropriate (e.g., comfortable) point in the up ordown swing of the first aircraft.

The two examples described above are merely exemplary and are notintended to be limiting. For example, although not described above, thefirst aircraft may be on the ground when it is coupled to the secondaircraft. In various embodiments due to a variety of factors (e.g.,aircraft performance limitations, land/air use restrictions (e.g.,zoning rules), the local environment (e.g., at ground level there isvery little clearance and/or footprint to be deposited and/or picked upusing a conventional takeoff and landing aircraft), etc.), the twoaircraft may be coupled and decoupled together in an appropriate manner.

In some other embodiments, some other coupling or transport technique orparadigm is used. For example, the second aircraft could “swallow” thefirst aircraft so that the first aircraft is completely surrounded bythe second aircraft. The first aircraft could dock in the secondaircraft (e.g., where the second aircraft may have multiple bays orslots for multiple aircraft to dock in). The second aircraft may pushthe first aircraft in front of it (e.g., instead of pulling or towingthe first aircraft behind the second aircraft). The second aircraftcould have a platform on which the first aircraft rests. The generalidea is that the first aircraft can fly beyond the range of itsremovable battery (and internal battery as well, if desired) by havingthe second aircraft expend its power to keep both aircraft airborne.

The following figures describe the above two-aircraft examples moregenerally and/or formally in flowcharts.

FIG. 13 is a flowchart illustrating an embodiment of a process to extendthe range of a first aircraft with the help of a second aircraft. Forexample, a first aircraft with range 1000 in FIG. 10 (e.g., given pickup(take off) location 1002) can make it to drop off location 1008 with thehelp of a second aircraft. In some embodiments, the example processshown herein is performed by the second aircraft.

At 1300, a first aircraft and a second aircraft are detachably coupled.See, for example, FIG. 11A and FIG. 12A. As described above, a varietyof coupling techniques, coupling or rendezvous locations (e.g., thefirst aircraft may be on the ground), and/or aircraft types (e.g., fixedwing, tilt wing, tilt rotor, etc.) may be used. In some embodiments, thefirst aircraft has a removable battery (see, e.g., FIGS. 1A-2B and FIGS.4 and 5) but for brevity those characteristics and/or properties are notdescribed in this example.

At 1302, the detachably coupled first aircraft and second aircraft areflown using the second aircraft, such that power to keep the detachablycoupled first aircraft and second aircraft airborne comes exclusivelyfrom the second aircraft and not the first aircraft. For example, thiscorresponds to resting the removable battery of the first aircraftduring the second leg (1006) of FIG. 10. See also FIG. 11B and FIG. 12Bwhere the second aircraft (1104 b and 1202 b, respectively) is providingall of the power to keep the two coupled aircraft airborne.

At 1304, the first aircraft and the second aircraft are decoupled. See,for example, FIG. 11C where the two aircraft are decoupled and then thefirst aircraft performs a vertical landing on its own power.Alternatively, in the example of FIG. 12C and FIG. 12D, the secondaircraft (1202 c/1202 d) swings the first aircraft (1200 c/1200 d) likea pendulum and deposits the first aircraft on the ground (e.g., with orwithout the first aircraft powering up its rotor).

FIG. 14 is a flowchart illustrating an embodiment of a process to extendthe range of a first aircraft with the help of a second aircraft. Insome embodiments, the process of FIG. 14 is performed in combinationwith the process of FIG. 13 (e.g., between steps 1302 and 1304). In someembodiments, the process is performed by the second aircraft. Asdescribed above, this may be a way for the second aircraft to decouplefrom the first aircraft without the second aircraft having to stop(e.g., because it needs to stay at or above a stall speed and cannotstop to detach the first aircraft).

At 1400, while the first aircraft and the second aircraft are detachablycoupled, the second aircraft is flown in a manner which causes the firstaircraft to swing. See, for example, FIG. 12C where the second aircraft(1202 c) descends, causing the first aircraft (1200 c) to swing forwardlike a pendulum.

At 1402, while the first aircraft is swinging, the second aircraft isflown in a manner which deposits the first aircraft on the ground. See,for example, FIG. 12D where the second aircraft (1202 d) has depositedthe first aircraft (1200 d) on the ground, in this example during thedownswing of the first aircraft. As described above, in someembodiments, the second aircraft deposits the first aircraft on theground when the first aircraft is at or near the apex of its(pendulum-like) swing.

In applications such as that described in FIG. 3 where an aircraft orother vehicle (e.g., which is powered by an internal battery and/or aremovable battery) can be dispatched to pick up and drop off anoccupant, power considerations should be taken into account so that thevehicle has sufficient power during all legs of the trip. The followingfigures describe some examples of such processes.

FIG. 15 is a flowchart illustrating an embodiment of a process torespond to a travel request based on an amount of stored charge in aremovable battery. In some embodiments, the process is performed by somecentral server (e.g., associated with a flight or other ride serviceprovider) which accepts or declines requests for travel.

At 1500, a travel request which includes a pickup location and a dropoff location is received. In the example of FIG. 3, a person at home(i.e., pickup location 302) who wants a ride to work would send a travelrequest which specifies the pickup location as their home (302) and thedrop off location as their work (304).

At 1502, an amount of travel-related charge associated with travelingbetween the pickup location and the drop off location is estimated. Forexample, in FIG. 3, this would correspond to estimating the amount ofcharge required to travel the second leg from pickup location (302) tothe drop off location (304). In various embodiments, this estimation isbased on the weight of the (unoccupied) aircraft, the weight of theoccupant, the weight of the removable battery, a selected flight path(e.g., to avoid no-fly zones, to stay within predefined travel corridorsor routes, etc.), and/or travel conditions (e.g., for an aircraft, morecharge would be required to fly when there is a headwind versus no windor a tailwind).

At 1504, an amount of stored charge in a removable battery is received.In some embodiments, to make it simpler and/or easier for the requesterand/or to prevent the requester from providing any false information,techniques to eliminate the requester from this exchange and/ortechniques to verify any provided information may be employed.

As an example of the former, the removable battery may have a built-inmeasurement module or block (e.g., which measures the amount of chargecurrent stored) and a built-in communication module or block (e.g.,which wirelessly sends the measured amount of stored charge over acellular data network or other wireless network to the server performingthe exemplary process).

As an example of the latter, there may be some verification code whichmust also be provided in addition to a provided or specified amount ofcharge (e.g., both of which are provided or otherwise input by the riderequester). For example, the removable battery may have two alphanumericdisplays: one which displays the amount of stored charge in theremovable battery and another display which displays a verification code(e.g., which depends both upon the amount of stored charge and someunpredictable and/or unknown (to the user) value). The server could thencompare both values to determine if the amount of stored chargespecified or otherwise provided by the ride requester is legitimate orotherwise accurate.

At 1506, it is determined if the amount of stored charge in theremovable battery exceeds the amount of travel-related charge. In thisexample, the process will accept the travel request if the amount ofstored charge in the removable battery is sufficient to power theaircraft or other vehicle between the pickup location and drop offlocation without running out of charge. For example, the decision atstep 1506 corresponds in FIG. 3 to deciding if the amount of storedcharge that the requester has in their removable battery is sufficientto fly or otherwise travel from pickup location 302 to drop off location304 (e.g., without assistance from the internal battery during thatsecond leg).

If so, the travel request is responded to, indicating that the travelrequest is accepted at 1508. Otherwise, some other step(s) are performedat 1510. In some embodiments, the travel request is accepted or rejectedbased solely on the stored charge in the removable battery. That is, itis not permissible to tap the resource of the internal battery when theoccupied aircraft or other vehicle travels from the pickup location tothe drop off location. In such embodiments, step 1510 would compriseresponded to travel request, indicating that the travel request is notaccepted (e.g., because the stored charge in the removable batterycannot sufficiently and solely provide power to travel from the pickuplocation to the drop off location, and this scenario does not permit theinternal battery to be tapped or otherwise used to supplement theremovable battery during this leg).

Alternatively, in some embodiments, the internal battery may be used tosupplement the removable battery during this leg between the pickuplocation and drop off location. The following figure describes anexample of step 1510 for such an embodiment.

FIG. 16 is a flowchart illustrating an embodiment of a process torespond to a travel request based on an amount of stored charge in aremovable battery and an amount of stored charge in an internal battery.In some embodiments, the process of FIG. 16 is used at step 1510 in FIG.15.

At 1600, a second amount of travel-related charge associated withtraveling between a starting location and the pickup location isestimated. The starting location is the location from which the vehiclebegins its trip. For example, in FIG. 3, where the aircraft is waitingat depot 300 to be deployed, the starting location is depot 300. Thesecond amount of travel-related charge estimated in FIG. 3 would be theamount of charge required for the unoccupied aircraft or other vehicleto travel the first leg of the trip from depot 300 to pickup location302.

In some cases, a vehicle is not waiting in a depot but is in use (e.g.,servicing some other and/or previous ride requester). In such cases, thestarting location may not necessarily be a depot, but rather the dropoff point of the previous requested ride (e.g., where as soon as thevehicle drops off the earlier ride requester, the vehicle, in thisexample at least, would go directly to the pickup location of the nextride requester).

At 1602, a third amount of travel-related charge associated withtraveling between the drop off location and an ending location isestimated. For example, in FIG. 3, this would be the amount of chargerequired for the unoccupied aircraft or other vehicle to travel thethird leg of the trip from drop off location 304 to depot 306 (which inthis example is the ending location).

Similar to the starting location, the ending location may depend uponwhether there is another, pending ride requester to be serviced. Forexample, if there is no next or pending ride request, then the endinglocation may be a depot. See, for example FIG. 3 where there is no nextor pending ride requester and the aircraft goes to depot 306.Alternatively, if there is a next and/or pending ride requester, thenthe ending location may be the next pickup location.

At 1604, an amount of stored charge in an internal battery is received.Since the aircraft or other vehicle may be unattended and/or unoccupiedat times, in some embodiments the internal battery includes a built-inmeasurement module or block as well as a built-in communication moduleor block, as described above with respect to the removable battery.

At 1606, it is determined whether a (first) sum of the amount of storedcharge in the removable battery (SC_(RB)) plus the amount of storedcharge in the internal battery (SC_(IB)) exceeds a (second) sum of thetravel-related charge associated with traveling between the pickuplocation and the drop off location (TRC) plus the second amount oftravel-related charge associated with traveling between a startinglocation and the pickup location (TRC₂) plus the third amount oftravel-related charge associated with traveling between the drop offlocation and an ending location (TRC₃).

If the decision at 1606 is Yes, then at 1608 the travel request isresponded to, indicating that the travel request is accepted. If thedecision at 1606 is No, then at 1610 the travel request is responded to,indicating that the travel request is not accepted.

Using FIG. 3 as an example, the decision at 16060 is equivalent todeciding whether each of the three legs shown there (e.g., with thecorresponding available batteries for each leg) has sufficient chargeavailable so as not to crash or otherwise stall during each leg. Forexample, during the second leg shown in FIG. 3, the removable batterywould be drained and the internal battery would be used to supplement orotherwise make up the difference for any additional charge required forthat second leg; the check at step 1606 would ensure that the first leg(when only the internal battery is available) and the third leg (whenagain only the internal battery is available) will have enough (e.g.,remaining) charge so as not to crash or otherwise stall.

Similarly, the server in some embodiments ensures that any aircraft orvehicle assigned to pick up an occupant or ride requester has aninternal battery with sufficient charge to complete all legs of the trip(e.g., assuming a single aircraft scenario where a second aircraft isnot used to tow the first aircraft). The following figure shows oneexample of this.

FIG. 17 is a flowchart illustrating an embodiment of a process to selecta vehicle from the pool of vehicles that is capable of providingsufficient charge for travel. In some embodiments, the process isperformed by a central server (e.g., associated with a flight or otherride service provider) which selects an aircraft or other vehicle from apool or fleet to service an accepted travel request.

At 1700, a pickup location and a drop off location are received. Forexample, as described above, these two pieces of information may beincluded in a travel request. In the example of FIG. 3, a travel requestwould specify pickup location 302 and drop off location 304.

At 1702, for each vehicle in a pool of vehicles, an amount of storedcharge in an internal battery is received. For example, if there are nvehicles in the pool, then stored charges (SC₁, SC₂, . . . , SC_(n-1),SC_(n)) would be received. As described above, there may be built-inmeasurement and/or communication modules or blocks to send or otherwisetransfer this information.

In some embodiments, all of the vehicles and internal batteries are thesame (e.g., with the same charge storage capacity), but some internalbatteries are only partially charged whereas others are fully charged.And even if all of the internal batteries are fully charged, due to age,wear, and/or slight manufacturing differences, there may be slightdifferences in the amounts of stored charge.

Alternatively, a pool of vehicles may include different types ofvehicles with different internal batteries having different chargestorage capacities (e.g., maximum amounts of stored charges). Forexample, there may be heavier vehicles with larger internal batteries aswell as lighter vehicles with smaller internal batteries.

At 1704, for each vehicle in the pool of vehicles, a second amount oftravel-related charge associated with traveling between a startinglocation and the pickup location is estimated, wherein the pool ofvehicles would use their internal battery to travel between theirstarting location and the pickup location. For example, (TRC_(2,1),TRC_(2,2), . . . , TRC_(2,n-1), TRC_(2,n)) would be estimated for a poolof n vehicles.

In the example of FIG. 3, the second amount of travel-related chargeestimated would be the amount of charge (e.g., for each vehicle) totravel the first leg from a starting location of depot 300 to pickuplocation 302. It is noted that this estimation may depend upon theunoccupied weight of the aircraft or vehicle (e.g., where some aircraftor vehicles in the pool may be heavier than others).

At 1706, for each vehicle in the pool of vehicles, a third amount oftravel-related charge associated with traveling between the drop offlocation and an ending location is estimated, wherein the pool ofvehicles would use their internal battery to travel between the drop offlocation and the ending location and the pool of vehicles would use aremovable battery to travel between the pickup location and the drop offlocation. For example, (TRC_(3,1), TRC_(3,2), . . . , TRC_(3,n-1),TRC_(3,n)) would be estimated for a pool of n vehicles.

In the example of FIG. 3, the third amount of travel-related chargeestimated would be the amount of charge (e.g., for each vehicle) totravel the third leg from drop off location 304 to an ending location ofdepot 306.

At 1708, a vehicle is selected from the pool of vehicles that has aninternal battery that is capable of providing sufficient charge fortravel based at least in part on the amount of stored charge, the secondamount of travel-related charge, and the third amount of travel-relatedcharge for each vehicle in the pool of vehicles. For example, for thefirst potential vehicle in the pool, its amount of stored charge (i.e.,SC₁) would be compared against the sum of its second amount oftravel-related charge (i.e., TRC_(2,1)) plus its third amount oftravel-related charge (i.e., TRC_(3,1)). If the former exceeded thelatter, then the first potential vehicle has sufficient charge for therequested trip. This process would be repeated for the other (n−1)potential vehicles in the pool. From the subset of vehicles which passthis test, a vehicle may be selected using any appropriate technique(e.g., closest to pickup location).

In some embodiments, the process of FIG. 17 is performed multiple times,as/if needed. In one example, during a first iteration of FIG. 17, thepool of vehicles excludes any vehicles that are in-use (i.e., onlyvehicles that are available and/or free are considered). For example,available and/or free vehicles may be in some depot waiting to bedeployed and may or may not be fully charged. This may ensure thatrequests are quickly responded to because the ride requester does notneed to wait for a vehicle to become free or otherwise available.

In some embodiments, if no suitable vehicles are found at step 1708during a first iteration that only considers free or available vehicles,the process of FIG. 17 is repeated, this time using or otherwiseconsidering vehicles which are in-use. The following figure shows oneexample of this.

FIG. 18 is a diagram illustrating an embodiment of a process to includein-use vehicles when selecting a vehicle from a pool, where the internalbattery of an in-use vehicle would not be charged prior to pickup of anext ride requester. As described above, in some embodiments, theexemplary process shown here is used during a second iteration of theprocess of FIG. 17 so that in-use vehicles may be considered. In someembodiments, the process is repeated for each in-use vehicle (e.g., sothat all in-use vehicles are considered). For convenience, steps whichare related between FIG. 17 and FIG. 18 are indicated using similarreference numbers.

At 1800, it is decided whether a vehicle is in use. For example, in FIG.3, if a vehicle is in the first leg (between depot or staring location300 and pickup location 302) or is in the second leg (between pickuplocation 302 and drop off location 304), then the vehicle is consideredto be in use. Alternatively, if the vehicle is in the third leg (betweendrop off location 304 and depot 306) or is waiting at depot 306, thenthe vehicle is considered to not be in use (i.e., it is free orotherwise available).

If the vehicle is determined to not be in use at 1800, then the processends. To clearly show that this process relates only to in-use vehicles,step 1800 is included.

Otherwise, if it is determined that the vehicle is in use at step 1800,the amount of stored charge in the internal battery for an in-usevehicle is set to be an amount of stored charge after an in-use vehicletravels to an in-use drop off location at 1702′. For example, in FIG. 3,suppose that an exemplary in-use vehicle is in the second leg of thetrip. The amount of stored charge would be set at step 1702′ to theamount of stored charge the in-use vehicle would have after dropping thefirst occupant or ride requester off at in-use drop off location (304).The use of the qualifier “in-use” is used to indicate or otherwisedesignate something related to the current ride or travel which makesthe vehicle in use as opposed to not in use.

In the context of FIG. 17, the amount of stored charge in the internalbattery set at step 1702′ in this process would be received by orotherwise input to the process of FIG. 17 at step 1702 in FIG. 17.

Returning to FIG. 18, at 1704′, the starting location for the in-usevehicle is set to be the in-use drop off location. To continue theexample from above where the in-use vehicle is in the second leg of thetrip shown in FIG. 3, the starting location (e.g., received by orotherwise input to the process of FIG. 17 at step 1704) is set to be the(in-use) drop off location (304).

In other words, what steps 1702′ and 1704′ do (e.g., within the contextor umbrella of FIG. 17) is enable consideration of an in-use vehiclewhere it is assumed that the in-use vehicle would be dispatched from theprevious drop off location directly to the new pickup location (e.g.,without going to a depot and/or without charging its internal battery).This may be faster (e.g., because no charging or intervening stop ispermitted before the next pickup), but obviously does not permitcharging of the internal battery.

At 1802, an amount of waiting time associated with the in-use vehicle isestimated. For example, this would be the amount of time a riderequester would be waiting if that particular in-use vehicle wereassigned to that ride requester. This may include whether the in-usevehicle has just picked up the current ride requester or is almost done,how far that ride is (e.g., if the current ride requester was justpicked up), and a distance from the in-use drop off location to thepickup location, etc.

At 1708′, a vehicle is selected from the pool of vehicles that has aninternal battery that is capable of providing sufficient charge fortravel and that has a shortest amount of waiting time based at least inpart on the amount of stored charge, the second amount of travel-relatedcharge, the third amount of travel-related charge, and the amount ofwaiting time for each vehicle in the pool of vehicles. In other words,the process will try to find the vehicle which will minimize the waitexperience by the ride requester while still ensuring that the assignedor otherwise selected vehicle has enough stored charge in its internalbattery to complete all legs of the trip.

In some embodiments, a second iteration of FIG. 17 which consideredin-use vehicles which are not permitted to be charged first (e.g.,before picking up the ride requester) fails to find a vehicle withsufficient charge (e.g., at step 1708 during a second iteration of FIG.17). In some such embodiments, a third iteration of FIG. 17 isperformed, where in-use vehicles are considered and they are permittedto be charged (at least partially) before picking up the ride requester.This may be the least desirable option because it further increases thewait time of the ride requester and is thus performed last. Thefollowing figure shows an example of this.

FIG. 19 is a diagram illustrating an embodiment of a process to includein-use vehicles when selecting a vehicle from a pool, where the internalbattery of an in-use vehicle is charged prior to pickup of a next riderequester. As described above, in some embodiments, the exemplaryprocess shown here is used during a third iteration of the process ofFIG. 17 so that in-use vehicles (after some charging) may be considered.In some embodiments, the process is repeated for each in-use vehicle(e.g., so that all in-use vehicles are considered). For convenience,steps which are related between FIG. 17 and FIG. 19 are indicated usingsimilar reference numbers.

At 1900, it is determined if a vehicle is in use. If it is determined tobe in use at step 1900, the amount of stored charge in the internalbattery for an in-use vehicle is set to be a predefined amount of storedcharge at 1702″. In this example, the internal battery of the in-usevehicle will be charged up to some predefined amount. For example, itmay be fully charged. Alternatively, to reduce wait time, the internalbattery may only be partially charged.

At 1704″, the starting location for the in-use vehicle is set to be acharging location. This is because the in-use vehicle will to a chargingstation (e.g., one of the depots shown in FIG. 3) to be charged beforepotentially picking up the ride requester. In some embodiments, thecharging location is between the in-use drop off location and the nextpickup location.

At 1902, an amount of waiting time associated with the in-use vehicle isestimate, including charging time at the charging location. For example,this may include completing the current trip, traveling to the chargingstation, charging time at the charging station, and traveling from thecharging station to the (next) pickup location.

At 1708″, a vehicle is selected from the pool of vehicles that has aninternal battery that is capable of providing sufficient charge fortravel and that has a shortest amount of waiting time based at least inpart on the amount of stored charge, the second amount of travel-relatedcharge, the third amount of travel-related charge, and the amount ofwaiting time, including the charging time, for each vehicle in the poolof vehicles. Again, this attempts to select the in-use vehicle that hasthe shortest waiting time while still ensuring that the internal battery(after charging) will have sufficient charge to complete all legs of thenext trip (e.g., for which a vehicle is being selected).

Although the foregoing embodiments have been described in some detailfor purposes of clarity of understanding, the invention is not limitedto the details provided. There are many alternative ways of implementingthe invention. The disclosed embodiments are illustrative and notrestrictive.

What is claimed is:
 1. (canceled)
 2. A vertical takeoff and landing(VTOL) aircraft, comprising: at least one rotor; a first battery; abattery compartment for a removable battery, wherein: the VTOL aircraftperforms a vertical landing at least once using the first battery whilethere is no removable battery in the battery compartment; after the VTOLaircraft performs the vertical landing at least once using the firstbattery, a removable battery is inserted into the battery compartment;and the VTOL aircraft performs a vertical takeoff at least once usingthe removable battery in the battery compartment while the removablebattery is in the battery compartment; and a coupler configured todetachably couple the VTOL aircraft to a second aircraft, wherein thesecond aircraft tows the VTOL aircraft via the coupler such that thesecond aircraft supplies the power to keep the VTOL aircraft and thesecond aircraft airborne.
 3. The VTOL aircraft recited in claim 2,wherein the VTOL aircraft and the second aircraft detachably couple viathe coupler while both the VTOL aircraft and the second aircraft areairborne.
 4. The VTOL aircraft recited in claim 2, wherein the VTOLaircraft and the second aircraft detach from each other while both theVTOL aircraft and the second aircraft are airborne.
 5. The VTOL aircraftrecited in claim 2, wherein the second aircraft includes a tilt rotoraircraft.
 6. The VTOL aircraft recited in claim 2, wherein: the secondaircraft includes a tilt rotor aircraft; the tilt rotor aircraft and theVTOL aircraft detachably couple via the coupler while at least one tiltrotor in the tilt rotor aircraft is in a hovering position; and at leastone tilt rotor in the tilt rotor aircraft is in a forward flightposition while the second aircraft tows the VTOL aircraft via thecoupler.
 7. The VTOL aircraft recited in claim 2, wherein the secondaircraft includes a fixed wing aircraft.
 8. The VTOL aircraft recited inclaim 2, wherein the VTOL aircraft and the second aircraft detach fromeach other including by: the second aircraft descends such that the VTOLaircraft is swung forward; on a downswing of the VTOL aircraft, the VTOLaircraft lands; and detaching the VTOL aircraft and the second aircraftafter the VTOL aircraft lands.
 9. A method, comprising: performing avertical landing at least once using a first battery in a verticaltakeoff and landing (VTOL) aircraft while there is no removable batteryin a battery compartment of the VTOL aircraft, wherein after the VTOLaircraft performs the vertical landing at least once using the firstbattery, a removable battery is inserted into the battery compartment;and performing a vertical takeoff at least once using the removablebattery in the battery compartment while the removable battery is in thebattery compartment, wherein the VTOL aircraft further includes acoupler that is configured to detachably couple the VTOL aircraft to asecond aircraft, wherein the second aircraft tows the VTOL aircraft viathe coupler such that the second aircraft supplies the power to keep theVTOL aircraft and the second aircraft airborne.
 10. The method recitedin claim 9, wherein the VTOL aircraft and the second aircraft detachablycouple via the coupler while both the VTOL aircraft and the secondaircraft are airborne.
 11. The method recited in claim 9, wherein theVTOL aircraft and the second aircraft detach from each other while boththe VTOL aircraft and the second aircraft are airborne.
 12. The methodrecited in claim 9, wherein the second aircraft includes a tilt rotoraircraft.
 13. The method recited in claim 9, wherein: the secondaircraft includes a tilt rotor aircraft; the tilt rotor aircraft and theVTOL aircraft detachably couple via the coupler while at least one tiltrotor in the tilt rotor aircraft is in a hovering position; and at leastone tilt rotor in the tilt rotor aircraft is in a forward flightposition while the second aircraft tows the VTOL aircraft via thecoupler.
 14. The method recited in claim 9, wherein the second aircraftincludes a fixed wing aircraft.
 15. The method recited in claim 9,wherein the VTOL aircraft and the second aircraft detach from each otherincluding by: the second aircraft descends such that the VTOL aircraftis swung forward; on a downswing of the VTOL aircraft, the VTOL aircraftlands; and detaching the VTOL aircraft and the second aircraft after theVTOL aircraft lands.
 16. A computer program product, the computerprogram product being embodied in a non-transitory computer readablestorage medium and comprising computer instructions for: performing avertical landing at least once using a first battery in a verticaltakeoff and landing (VTOL) aircraft while there is no removable batteryin a battery compartment of the VTOL aircraft, wherein after the VTOLaircraft performs the vertical landing at least once using the firstbattery, a removable battery is inserted into the battery compartment;and performing a vertical takeoff at least once using the removablebattery in the battery compartment while the removable battery is in thebattery compartment, wherein the VTOL aircraft further includes acoupler that is configured to detachably couple the VTOL aircraft to asecond aircraft, wherein the second aircraft tows the VTOL aircraft viathe coupler such that the second aircraft supplies the power to keep theVTOL aircraft and the second aircraft airborne.
 17. The computer programproduct recited in claim 16, wherein the VTOL aircraft and the secondaircraft detachably couple via the coupler while both the VTOL aircraftand the second aircraft are airborne.
 18. The computer program productrecited in claim 16, wherein the VTOL aircraft and the second aircraftdetach from each other while both the VTOL aircraft and the secondaircraft are airborne.
 19. The computer program product recited in claim16, wherein the second aircraft includes a tilt rotor aircraft.
 20. Thecomputer program product recited in claim 16, wherein: the secondaircraft includes a tilt rotor aircraft; the tilt rotor aircraft and theVTOL aircraft detachably couple via the coupler while at least one tiltrotor in the tilt rotor aircraft is in a hovering position; and at leastone tilt rotor in the tilt rotor aircraft is in a forward flightposition while the second aircraft tows the VTOL aircraft via thecoupler.
 21. The computer program product recited in claim 16, whereinthe VTOL aircraft and the second aircraft detach from each otherincluding by: the second aircraft descends such that the VTOL aircraftis swung forward; on a downswing of the VTOL aircraft, the VTOL aircraftlands; and detaching the VTOL aircraft and the second aircraft after theVTOL aircraft lands.